Many aloes like shade in Phoenix.

Try sunset's plant finder, and put in "shade" for Zone 13 and all sorts of things come up.

Here is a link that might be useful: Plant Search for you

Welcome to the forum and to the joys and frustrations of home ownership, LOL. :) Please post often as you develop your garden (and feel free to comment on other folk's posts too of course).

I've got a similar bed right at the base of the north side of my house and I've had great luck for years with Aloe vera plants. So good in fact, they got a little TOO fat/wide/happy there that they were reaching out into the little walkway from my driveway to my front door. Eventually I ripped them out and replanted them elsewhere and replaced them with less-wide-growing Aloe saponaria (aka "Aloe maculata"). Those have done awesome too and don't get quite as wide.

Your idea about cast iron plants is good, alhtough they'll need a bit more water and if we have a HARD freeze they will look awful for months, but it's not a bad choice at all. :) Sago "palms' would be good choices too, just keep in mind they are very wide so might not fit the space, but otherwise are good choices too. Good ol' portulacaria (not Portulaca) is good too, it's sometimes called "dinosaur food" or "elephant's food". It's a relative of the jade plant but with much smaller leaves, more branches, AND it survives our weather just fine.

Let us know what you select and how it works out. Even an empty small bed with nice smooth river rock is better than bare hardpan, LOL, so you're on the right track.

Take care and keep us posted!
Grant

Here is a link that might be useful: Grant's garden pics so far Feb 2012